HID: do not init input reports for Win 8 multitouch devices

Some multitouch screens do not like to be polled for input reports.
However, the Win8 spec says that all touches should be sent during
each report, making the initialization of reports unnecessary.
The Win7 spec is less precise, so do not use this for those devices.

Add the quirk HID_QUIRK_NO_INIT_INPUT_REPORTS so that we do not have to
introduce a quirk for each problematic device. This quirk makes the driver
behave the same way the Win 8 does. It actually retrieves the features,
but not the inputs.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Tested-by: Srinivas Pandruvada<srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index c28ef86c7c67..ac28f08c3866 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -951,6 +951,18 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	hdev->quirks |= HID_QUIRK_MULTI_INPUT;
 	hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;
 
+	/*
+	 * Handle special quirks for Windows 8 certified devices.
+	 */
+	if (id->group == HID_GROUP_MULTITOUCH_WIN_8)
+		/*
+		 * Some multitouch screens do not like to be polled for input
+		 * reports. Fortunately, the Win8 spec says that all touches
+		 * should be sent during each report, making the initialization
+		 * of input reports unnecessary.
+		 */
+		hdev->quirks |= HID_QUIRK_NO_INIT_INPUT_REPORTS;
+
 	td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);
 	if (!td) {
 		dev_err(&hdev->dev, "cannot allocate multitouch data\n");